OpticalFit Manual 18.06	Table of contents	Luminescence database	« Last page	Next page »

Spectra in the luminescence database

Some emission line entries in the luminescence database also have an associated spectrum, which may be displayed in the OpticalFit spectrum plot to compare with other measured spectra. Spectra can be plotted using either the compact or expanded views of the luminescence database, although the latter gives the user greater control in choosing which spectra to plot.

Plotting spectra using the 'compact' view

When using the 'compact' view of the luminescence database, reference spectra can be shown by checking the 'Show spectra' checkbox, as shown below.

Enabling the 'Show spectra' checkbox in the 'compact' view of the luminescence database.

If any of the reference lines in the current search results include a spectrum, those spectra will be overlaid on the current plot window, as shown below.

Three reference spectra overlaid on a measured spectrum.

Three reference spectra (in red, green, and blue) overlaid on a measured spectrum (in grey).

Normalisation is automatically applied when reference spectra are displayed.

In the above example, the ‘Benitoite-20kV-10nA-100um’ spectrum shown in grey is a measured spectrum, and the three other spectra (red, green, blue) are from references in the database. Note also that the colour of the spectrum matches the background colour band for the associated luminescence line markers. For example, the spectrum displayed in blue (labelled ‘Ti [3+] in Benitoite, Gaft et al. 2005’ in the spectrum legend) corresponds to the second row of line markers, which are also shown in blue and labelled ‘Ti [3+] in Benitoite, Gaft et al. 2005’.

Some materials have a considerable number of reference spectra, which, if all plotted together, make for a confusing display. For example, there are currently eight reference spectra for xenotime (YPO₄):

All reference spectra for xenotime plotted at once.

In cases where there are too many reference spectra, the user may wish to refine the search results using the secondary search drop-down list, as shown below.

Using the secondary search drop-down list to refine search results.

The two spectrum plots below show the effect of plotting the spectra for only one emitter at a time (in these cases, Dy and Tm).

Reference spectrum of Dy 3+ in xenotime overlaid on a measured xenotime spectrum.

Reference spectrum of Tm 3+ in xenotime overlaid on a measured xenotime spectrum.

Two plots showing single reference spectra overlaid on a measured spectrum, achieved by selecting only one emitter at a time using the secondary search drop-down list.

Alternatively, users may wish to select which spectra to plot using the 'expanded' view of the luminescence database window, as described next.

Plotting spectra using the 'expanded' view

The 'expanded' view of the luminescence database window retains the 'Show spectra' checkbox of the 'compact' view, as described above, which can still be used to show or hide all of the spectra from the current search results. However, the 'expanded' view also has button controls for each spectrum, which allow the user to show one or more spectra without having to show all or none.

If a line entry has an associated spectrum, the entry will have a button in the 'Spectrum' column, as shown below.

Line entries in the database with associated spectra are indicated with buttons in the 'Spectrum' column.

The 'Spectrum' column is only shown if at least one of the entries in the current search results has an associated spectrum.

To show a particular spectrum, left-click on the appropriate spectrum column button (e.g. 'Benitoite, Gaft et al. 2005', in example below):

Selecting a single reference spectrum in the 'Luminescence database' window by enabling one button in the 'Spectrum' column.

With the spectrum column button enabled, the spectrum from that reference will be displayed in the OpticalFit spectrum plot:

A single reference spectrum shown in the OpticalFit spectrum plot. The measured spectrum is in black, and the reference spectrum is in green.
Note the spectrum colour matches the colour background in the 'Emitter' column in the 'Luminescence database' window, above.

To plot several reference spectra at once, simply select several buttons. In the example below, two reference spectra have been selected at the same time using the 'Spectrum' column buttons.

Selecting multiple reference spectra in the 'Luminescence database' window by enabling multiple buttons in the 'Spectrum' column.

Multiple reference spectra shown in the OpticalFit spectrum plot. Measured spectrum is in black, two reference spectra are in green and red.
Note spectrum colours match the colour background in the 'Emitter' column in the 'Luminescence database' window, above.

Careful observers may note that three spectrum column buttons are enabled in the 'Luminescence database' window above, whilst only two reference spectra are displayed in the spectrum plot. This is because both of the Cr³⁺ lines from the Gaft et al. reference are from the same reference spectrum, so pressing the spectrum column button for one of these lines automatically enables the other, and the associated spectrum is only displayed once.